INHIBITORY LEFT ATRIAL INFLUENCES ON THE BAROREFLEX

左心房对压力反射的抑制性影响

• 批准号: 3358682
• 负责人: DAVID J RAMSAY
• 金额: $ 17.19万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 1992-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3358682
• 关键词: adrenocorticotropic hormone; atrial natriuretic peptide; atrium; baroreceptors; blood volume; dogs; homeostasis; hormone regulation /control mechanism; hypotension; hypovolemia; intracardiac pressure; neurohormones; renin; secretion; thirst; vasopressins

The long-term objective of the proposed studies is to evaluate the contribution of low and high pressure baroreceptors in the neurohumoral responses to simulated hypovolemia. Reduction in venous return leads to stimulation of renin, vasopressin and ACTH secretion and to drinking. These mechanisms, together with the sympathetic nervous system stabilize blood pressure and act synergistically to return fluid balance to normal. The overall hypothesis is that unloading baroreceptors in the left atrium is essential for the expression of these neurohumoral responses to simulated hypovolemia. Differential changes in pressure will be achieved by graded constriction of cuffs placed around the thoracic portion of the inferior vena cava, pulmonary artery, ascending aorta and abdominal aorta proximal to the renal arteries. The hypothesis that increases in left atrial, rather than left ventricular, pressure inhibit vasopressin, renin and ACTH secretion and drinking when arterial blood pressure is reduced by ascending aortic cuff constriction will be tested. Techniques of maintenance of normal left atrial pressures and selective ventricular denervation during aortic constriction will be used. The effects of raised right atrial pressure on the neurohumoral response to arterial hypotension will be evaluated using pulmonary artery constriction. Inflation of a balloon in the pulmonary vein/left atrium junctional region will be used to assess the effects of increasing afferent discharge without release of atrial natriuretic factor (ANF), and compared with inflation of a balloon placed at the mitral valve orifice which increases afferent discharge and ANF release. It is anticipated that both left atrial baroreceptors and ANF contribute to the inhibition of renin, vasopressin and ACTH release and drinking when left atrial pressure increases. The contribution of the sympathetic nervous system to inhibition of renin secretion when left atrial pressure increases will be assessed by measurement of plasma epinephrine and measurement of renal nerve activity. Thus it is anticipated that the essential role of the left atrium in hormonal and thirst responses to simulated hypovolemia will be established and that the mechanism of these interactions will be elucidated.

拟议研究的长期目标是评估 低压和高压压力感受器的贡献 对模拟低血容量的神经体液反应。 减少 静脉回流会刺激肾素、加压素和促肾上腺皮质激素 分泌和饮用。 这些机制与 交感神经系统稳定血压并发挥作用 协同作用使体液平衡恢复正常。 整体 假设左心房压力感受器的卸载是 这些神经体液反应的表达至关重要 模拟低血容量。 压力的差异变化将是 通过围绕胸部放置的袖带分级收缩来实现 下腔静脉、肺动脉、升支部分 主动脉和腹主动脉靠近肾动脉。 这 假设左心房增加，而不是左心房增加 心室压力抑制加压素、肾素和ACTH的分泌 当动脉血压升高而降低时饮酒 将测试主动脉袖收缩情况。 保养技巧 正常左心房压力和选择性心室压力 将在主动脉缩窄期间使用去神经术。 效果 右心房压力升高对神经体液反应的影响 将使用肺动脉评估动脉低血压 收缩。 肺静脉/左侧气球充气 心房交界区将用于评估 增加传入放电而不释放心钠素 因子（ANF），并与放置在 二尖瓣口，增加传入放电和 ANF 发布。 预计左心房压力感受器和 ANF 有助于抑制肾素、加压素和 ACTH 当左心房压力增加时释放和饮用。 这 交感神经系统对抑制的贡献 当左心房压力升高时，肾素分泌量 通过测量血浆肾上腺素和测量 肾神经活动。 因此，预计必要的 左心房在荷尔蒙和口渴反应中的作用 将建立模拟低血容量，其机制 这些相互作用将被阐明。